Cambridge, UK, 3rd May 2011. Astex Therapeutics, the UK-based biotechnology company developing targeted therapies for oncology and virology, announced that it has achieved multiple early milestones in its fragment-based drug discovery collaboration with GlaxoSmithKline which commenced in November 2009. Total milestone payments received under the collaboration have now reached £5.9 million.

The milestones relate to the application of Astex’s Pyramid™ fragment based screening platform, against a number of molecular targets of interest to GSK. Following the identification of validated fragment hits, the joint project teams prioritise fragments to be taken into lead optimization with the intention of selecting clinical development candidates for further development by GSK.

Commenting on the achievement of the early milestones, Dr Harren Jhoti, Astex’s Chief Executive Officer said, “We are delighted to have achieved these initial milestones within 18 months of beginning our collaboration with GSK. This achievement is testament, not only to the power of Astex’s technology to rapidly deliver novel chemical start points against challenging disease targets, but is also a reflection of how well the Astex-GSK joint project teams are working together in the collaboration.

For more information, please contact:

Astex Therapeutics Ltd

Jeremy Carmichael, PhD

Director of Business Development

Tel: +44(0)1223 226200

Email: j.carmichael@astex-therapeutics.com

Press & Media Enquiries

College Hill

(Europe) Melanie Toyne Sewell / Daniel Gooch

Tel: +44 20 7866 7866

(US) Rebecca Skye Dietrich

Tel: +1 857 241 0795

Email: astex@collegehill.com

About Astex Therapeutics

Astex is a UK-based biotechnology company that discovers and develops novel small molecule therapeutics. Using its pioneering fragment-based drug discovery platform Pyramid™, Astex has built a pipeline of molecularly-targeted oncology drugs, of which three are currently being tested in clinical trials with others in discovery and pre-clinical development.
In addition to its proprietary research programmes, Astex’s productivity in lead discovery has been endorsed through numerous partnerships with major pharmaceutical companies, including AstraZeneca, Bayer-Schering, Boehringer Ingelheim, GlaxoSmithKline, Novartis and Johnson & Johnson.

On April 6th 2011, Astex announced that it had entered into a definitive merger agreement with SuperGen, Inc., a NASDAQ listed company, to form a financially strong, oncology focused, company, to be called Astex Pharmaceuticals, Inc.

For further information on Astex please visit the Company’s website at www.astex-therapeutics.com